Electron transfer in Cobalt complexes using rigid ferrocenyl decorated polypyridyl based ligands

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Electron transfer processes are important steps in many chemical reactions. These processes proceed on very different time scales. Within this project hetero bimetallic complexes will be synthesized, after oxidation an intramolecular electron transfer will be found from a cobalt(II/III) ion to a ferrocenyl substituent. The employed hexadendate ligand around the cobalt ion is chosen that: on the one hand stable cobalt(II) complexes are formed, with high activation barrier for the oxidation to the cobalt(III) complex and on the other side the free reaction energy is low. Due to these properties the complex can be found in two metastable states that interconvert slowly.The large structural changes within the ligand sphere of the cobalt complexes stabilize the two states making them observable side by side at comparable high temperatures.Both states might be addressable by external stimuli like temperature change or light irradiation, making these molecules interesting for applications in data storage and molecular switches. Of high interest is the possible occurrence of an MMCT absorption (Metal to Metal Charges Transfer) accompanied with CTIST (Charge Transfer Induced Spin Transition) which allows inducing an electron transfer by irradiation of light.The electron transfer process will be studied in detail by means of electro chemical, nuclear and electron spin resonance spectroscopy as well as UV/Vis/NIR spectroscopy.